For this purpose 3 parallel groups of 20 healthy men will be formed. One group will be treated with ezetimibe (10 mg/day), one with 40 mg/day of simvastatin and another with ezetimibe (10 mg/day) plus simvastatin (40 mg/day). Each treatment period will last for 2 weeks. Blood drawing will be per-formed at baseline (before the initiation of treatment) and at the end of the 2 weeks. (storing of the samples at -80°). The measurements involved in this study include the determination of the lipopro-tein concentrations in serum, isolation of the mononuclear cells, measurement of LDL receptor mRNA from the peripheral blood mononuclear cells, measurement of HMG-CoA reductase mRNA levels in peripheral blood mononuclear cells, measurement of the LDL-receptor protein concentrations on the surface of peripheral blood mononuclear cells. Furthermore, the serum latosterol to cholesterol con-centrations will be measured as a surrogate marker of the HMG-CoA reductase activity.